Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
When your motion-control build demands tight tolerances and reliable torque transfer, a poorly matched gear becomes the weakest link in the chain. Engineers, robotics builders, and CNC hobbyists who need a dependable 2.5 modulus spur pinion gear will find this stepped-hub design eliminates shaft slippage and simplifies motor coupling across a wide range of drive configurations.
Each gear is machined from 45# carbon steel, offering a solid balance of hardness and machinability. The stepped hub design allows the gear to seat flush against motor flanges or bearing housings. Tooth counts range from 15T to 32T, with bore diameters from 12 mm (0.47 in) up to 40 mm (1.57 in) and matching keyway slots from 4 mm to 12 mm to lock the gear firmly to the shaft.
These 2.5 mod pinion gears are well-suited for DIY CNC router Z-axis drives, stepper motor gear reduction stages in 3D printer extruder assemblies, and light industrial conveyor or actuator systems where a compact spur gear pair is needed for precise linear or rotary motion control.
Machined from 45# carbon steel for reliable hardness, wear resistance, and dimensional stability under continuous load in motor drive applications.
Standard 2.5 mod tooth geometry ensures smooth meshing with compatible mating gears, minimizing backlash and noise in CNC and automation builds.
Available with pre-cut keyway slots (4 mm, 5 mm, 6 mm, 8 mm, 10 mm, or 12 mm) matched to bore diameter, providing positive shaft locking without set-screw slippage.
The integrated step on the hub allows the gear to register against motor flanges or bearing faces, simplifying axial positioning during assembly.
Ten tooth-count options from 15 to 32 teeth let you dial in the gear ratio you need for stepper motor drives, servo systems, or custom reduction stages.
"Process Hole" variants ship with a pilot bore ready for finish machining, giving machinists full control over final bore diameter and fit class.
| Modulus | 2.5 |
|---|---|
| Tooth Count | 15T, 16T, 18T, 20T, 22T, 24T, 25T, 28T, 30T, 32T |
| Material | 45# Carbon Steel |
| Hub Style | Stepped Hub |
| Bore Diameter Options | Process Hole; 12, 14, 15, 16, 18, 20, 22, 24, 25, 28, 30, 32, 35, 40 mm |
| Keyway Width Options | 4 mm, 5 mm, 6 mm, 8 mm, 10 mm, 12 mm (matched to bore) |
| Pressure Angle | 20° |
| Surface Finish | See variant options |
| Quantity per Order | 1 PCS |
| Compatible Gear Type | 2.5 Modulus Spur Gear |
Select the tooth count based on your desired gear ratio. Divide the driven gear's tooth count by the pinion's tooth count to get the ratio. For example, pairing a 15T pinion with a 30T gear gives a 2:1 reduction. Lower tooth counts produce higher reduction ratios; higher tooth counts reduce the ratio and increase output speed.
"Process Hole" means the gear ships with a rough pilot bore that is not finished to a specific diameter. It is intended for machinists who want to bore the hole to a precise fit class on a lathe. It cannot be used as-is on a standard motor shaft — finish boring is required before installation.
45# carbon steel (equivalent to AISI 1045) has a tensile strength of approximately 600–700 MPa in the normalized condition. It is suitable for moderate-load spur gear applications such as CNC drives, stepper motor stages, and light conveyor systems. For very high-torque or shock-load environments, consider heat-treated or alloy steel gears.
45# carbon steel is not inherently corrosion-resistant. For indoor, dry environments this is generally not a concern with normal maintenance. If your application involves moisture, coolant, or outdoor exposure, apply a light machine oil coating or consider a gear with a protective surface treatment. Contact us to confirm available finish options.
Check your motor shaft's keyway specification in the motor datasheet — it will list the key width and depth. Match the bore diameter to your shaft diameter and select the keyway width that corresponds to the standard key for that shaft size. For example, a 20 mm shaft typically uses a 6 mm key per DIN 6885 standards.
Yes, provided the rack is also 2.5 modulus and uses a matching 20° pressure angle. This is a common configuration for CNC router axes and linear actuators. Ensure the rack tooth profile is compatible before ordering.
The stepped hub provides a shoulder that registers against a motor face or bearing, making axial positioning easier and more repeatable during assembly. A standard spur gear without a step requires additional spacers or careful measurement to achieve the same axial alignment.
